ssh-short
The aim of ssh-short is reduce the amount you have to type when ssh-ing into common hosts, from something like:
ssh -i /path/to/my/key.pem [email protected]
to:
sshort 16
or even an alias if you set one:
sshort fav
The command sshort was chosen because it's easy and quick to type,
even if it's not the most descriptive name (suggestions welcome!)
Config
If you often ssh into a set of hosts that have similar IPs with a common username (such as Amazon EC2 instances),
then ssh-short can use a combination of config and map files to reduce the repetitive typing when ssh-ing into these hosts.
You first create a config file (~/.ssh-short/config.yml) like the following:
---
:keys_dir: '~/my/ssh/keys'
:ip_mask: 10.55.2.0
:default_user: my-user
keys_dir
This is where ssh-short will look for your ssh keys, it assumes that they're all in here
ip_mask
The mask provides a way of avoiding having to type the full IP every time.
If all your IPs start with 10.55.2 for example, then set the mask to 10.55.2.0,
now you only have to provide the last segment and ssh-short will add what's missing
using the sections from the mask.
Any sections you pass in overwrite the mask, so you can still connect to IPs that
are completely different from the mask
Here's an example of masks, input and outputs
| Mask | Input | Result |
|---|---|---|
| 10.55.2.0 | 16 | 10.55.2.16 |
| 10.55.2.0 | 2.16 | 10.55.2.16 |
| 10.55.2.0 | 55.2.16 | 10.55.2.16 |
| 10.55.2.0 | 10.55.2.16 | 10.55.2.16 |
| 10.55.2.0 | 192.168.1.2 | 192.168.1.2 |
| 10.60.0.0 | 16 | 10.60.0.16 |
| 10.60.0.0 | 22.2 | 10.60.22.2 |
| 10.60.0.0 | 222.22.2 | 10.222.22.2 |
default_user
Hopefully this is self explanatory, it's the username that will be used to connect to the host if no user is provided.
You can override the user for a node, see args section below
Keys
When you connect to a host for the first time with ssh-short, it will scan your keys_dir
and present you with a list of numbered keys:
Update: As of version 0.2.0 your default SSH Key (id_rsa) can now be used and will be presented as option 0
user@localhost $ sshort 16
Select a key:
0) id_rsa
1) Dev.pem
2) Test.pem
3) Admin.pem
Simply type the number of the key and press enter. ssh-short will connect you via ssh,
and it will also remember your choice in ~/.ssh-short/nodemap.yml so the next time you connect
it will look for the key name in the nodemap file and use that automatically:
user@localhost $ sshort 16
Connecting as my-user to 10.55.2.16 using Test.pem
...
It stores the name of the file (e.g. Test.pem), not the number you select, or the full path to the key.
This way if you add keys or change your keys directory it doesn't matter,
as long as the file name stays the same
If you chose the wrong key or need to change the key, see args section below
Args
-u
Specify a user. This will be used instead of the defualt user. The user is saved in the nodemap so you only have to set it once. If the user does change, use this command to update the nodemap:
user@localhost $ sshort 16
Connecting as my-user to 10.55.2.16 using Test.pem
...
user@localhost $ sshort 16 -u new-user
Connecting as new-user to 10.55.2.16 using Test.pem
...
user@localhost $ sshort 16
Connecting as new-user to 10.55.2.16 using Test.pem
...
-k
This forces an update to the key for a node and you will be presented with the list of keys again as if connecting for the first time:
user@localhost $ sshort 16 -k
Select a key:
0) id_rsa
1) Dev.pem
...
-a
Add an alias to a node, or move an exisiting alias to a new node, see Aliases section below
Aliases
If you want to connect to a host using an alias instead of an IP, you can set an alias
sshort 16 -a fred
Next time you can just use fred
sshort fred
If you set an alias that already exists it will be moved to the new host, and a message will inform you:
user@localhost $ sshort 0.77 -a fred
Moving alias fred from 10.55.2.16 to 10.55.0.77
...
To list all the saved aliases, use the --list action:
user@localhost $ sshort --list
fav
fred
Push and Pull
ssh-short also provides a way to push/pull files using scp:
sshort 16 --pull /foo/bar.txt /tmp/
This will pull the file /foo/bar.txt from the host to the /tmp directory on your local machine.
The opposite is --push:
sshort 16 --push /tmp/bar.txt /foo/
Behind the scenes ssh-short uses the same key lookup process,
and then just passes the path arguments to scp:
scp -r -i /path/to/key.pem /tmp/bar.txt [email protected]:/foo/
Installation
Install the gem:
gem install ssh-short
Create your config file
SSH Config
The SSH config file (~/.ssh/config) has support for a lot of this already, as well as extra stuff like LocalForward etc
Maybe this tool can evolve to use the SSH config for persistence instead of ~/.ssh-short/nodemap.yml
and support all the features that SSH and it's config file offer,
however reading and writing wouldn't be as simple as serialising a simple array to/from YAML.
Plus the user might want to make changes to the SSH config outside of ssh-short, so we'd have to careful not to overwrite these "external" changes
ToDo
- Make
ip_maskanddefault_useroptional config settings - IPv6??